Internal combustion engine cranking motor energizing circuit

ABSTRACT

The pull-in coil of a cranking motor solenoid, having pull-in and hold-in coils, and a resistor connected in parallel therewith are connected in series with the cranking motor of an internal combustion engine electrical crqnking system. Upon the energization of the cranking motor solenoid, the solenoid aramture is actuated in a direction to effect the operation, through a shift mechanism, of the cranking motor pinion gear, slidably mounted upon the cranking motor shaft, into engagement with the cranking gear of the engine. In the event of the abutment of the teeth of the pinion and cranking gears, the cranking motor is energized at low power through the parallel combination of the solenoid pull-in coil and resistor to provide sufficient torque to slowly rotate the pinion gear until the teeth thereof are in register with and, consequently, mesh with, the teeth of the cranking gear. Upon the meshing of the teeth of the pinion and cranking gears, the solenoid armature is actuated to the full extent of its travel to a position at which an electrically conductive member carried thereby bridges two electrical contacts located in the cranking motor solenoid housing to complete the energizing circuit of a power relay which connects the cranking motor directly across the direct current potential source.

[ Feb. 18, 1975 v INTERNAL COMBUSTION ENGINE CRANKING MOTOR ENERGIZINGCIRCUIT [75] Inventor: Satish M. Chohan, Bolingbrook, Ill.

[73] Assignee: General Motors Corporation,

Detroit, Mich.

[22] Filed: Feb. 4, 1974 [2l] Appl. No.: 439,287

[57] ABSTRACT The pull-in coil of a cranking motor solenoid, havingpull-in and hold-in coils, and a resistor connected in paralleltherewith are connected in series with the cranking motor of an internalcombustion engine electrical crqnking system. Upon the energization ofthe cranking motor solenoid, the solenoid aramture is actuated in adirection to effect the operation, through a shift mechanism, of thecranking motor pinion gear, slidably mounted upon the cranking motorshaft, into engagement with the, cranking gear of the engine. In

521 U.S. Cl 290/38, 290/37, 74/6, the event of the abutment 9f the teethof the Pinion 123/179 and cranking gears, the cranking motor isenergized at [51] Int. Cl. H02p 9/04 low power through the parallel minati n f th s [58] Field of Sear h 290/36, 37, 38; 123/179 B; lenoidpull-in coil and resistor to provide sufficient 74/ torque to slowlyrotate the pinion gear until the teeth thereof are in register with and,consequently, mesh [56] References Cit d with, the teeth of the crankinggear. Upon the meshing UNITED STATES PATENTS of the teeth of the pinionand cranfiing gears the sole] noid armature is actuated t0 the fu extent0 its trave iilii? 231322 2211201501j11:11j:jjjjiiijiiiiiiif932i2 to aPosition at which 3 electrically eenductive 3-171368 4/1965 Semy v M290/37 ber carried thereby bridges two electrical contacts lo- 3.3995769/1968 Seillv et a]. 290/38 cated in the cranking motor Solenoid housingto 3,433,968 3/1969 Broyden 290/38 plete the g ng i uit f a power relaywhich connects the cranking motor directly across the direct PrimaryExaminerfiG. R. Simmons current po enti l source. Attorney, Agent, orFirm-Richard G. Stahr 7 Claims 4 Drawing Figures L m n n if. I 5

Ullllllll INTERNAL COMBUSTION ENGINE CRANKING MOTOR ENERGIZING CIRCUITThis invention is directed to an internal combustion engine crankingmotor energizing circuit and, more specifically, to an energizingcircuit of this type which provides for improved engagement capabilitybetween the cranking motor driven pinion gear and the cranking gear ofthe associated internal combustion engine.

The internal combustion engine cranking system commonly employed forelectrically cranking internal combustion engines includes an electriccranking motor having an extended shaft provided with a helical spline,a pinion gear slidably mounted upon and rotated by the extended motorshaft, a shift mechanism operable to axially slide the pinion gear inone direction to engage and in an opposite direction to disengage thepinion gear and the cranking gear of the associated internal combustionengine and an electrical solenoid having at least one operating coil andan armature actuated thereby in operative engagement with the shiftmechanism. The armature of the solenoid is normally operated to a firstposition by a compression or tension spring to effect the disengagementof the pinion and engine cranking gears and is operated upon theenergization of the solenoid, by a starting switch operable at volition,to a second position to effect the engagement of the pinion and enginecranking gears. When the meshing is nearly completed, the armatureoperates a master switching device which serves to connect the electriccranking motor across a source of direct current potential, such as aconventional storage battery. Internal combustion engine electricalcranking systems of this type are well known in the internal combustionengine art.

When the electrical engine cranking sequence is initiated upon theoperation of the starting switch, the cranking motor solenoid isenergized. Upon the energization of the cranking motor solenoid, thearmature constant. The end result is that the solenoid force isincapable of overcoming the tooth surface friction and hence cannotindex the pinion gear.

Since a successful indexing of the pinion gear upon encountering piniongear-cranking gear tooth abutment determines whether or not piniongear-cranking gear tooth mesh is obtained, a turning torque supplied byrotating the cranking motor armature is one method of indexing thepinion gear without total dependence upon solenoid force. Rotating thecranking motor armature simultaneously with the energization of thecranking motor solenoid, however, is hazardous since the armatureobtains a high speed with full power to the motor and would damage thecranking gear of the engine in the process of mesh. Consequently, anarrangement to provide cranking motor armature rotation at low speedduring the pinion gear-cranking gear engagement function while retainingthe protective feature of providing full power to the cranking motoronly when complete pinion gear-cranking gear engagement is obtained, isdesirable.

It is, therefore, an object of this invention, to provide an improvedinternal combustion engine cranking systern.

It is another object of this invention to provide an improved internalcombustion engine cranking motor en ergizing circuit.

It is a further object of this invention to provide an improved internalcombustion engine cranking motor energizing circuit which provides forthe low power enthereof is actuated and operates the shift mechanism toslide the pinion axially in a direction toward a meshing engagement withthe internal combustion engine cranking gear. If the pinion and crankinggears properly engage, the solenoid armature will be actuated to thefull extent of its travel and close contacts which actuate controlcircuits to energize the cranking motor directly across the associateddirect current power supply or battery. This arrangement insures thatpower is not applied to the cranking motor until pinion gearcrankinggear mesh is realized. If tooth abutment occurs between the pinion andcranking gears, the spiral spline on the extended shaft of the crankingmotor produces a rotation of the pinion gear which indexes this gear toa new position which permits proper meshing with the cranking gear.While this arrangement appears to be functional in theory, in actualapplications in the field it has proven to be, in some instances,unsatisfactory. This arrangement relies upon the force of the crankingmotor solenoid to produce an indexing rotation of the pinion gear invthe event of pinion gearcranking gear tooth abutment. A major portionof the solenoid force is used in overcoming the drive assembly returnspring load, consequently, only the small remaining force is availablefor the actual indexing of the pinion gear. Consequently, a drop insupply potential or a heated solenoid from repeated cranking attemptsresults in a considerable lower available force for indexing the piniongear as the return spring load remains ergization of the cranking motorsimultaneously with the energization of the cranking motor solenoidwhereby the cranking motor provides a torque which will index the piniongear into a position in mesh with the cranking gear of the engine andprevents the application of full power to the cranking motor untilcomplete pinion gear-cranking gear mesh is obtained.

In accordance with this invention, an improved internal combustionengine cranking motor energizing circuit is provided wherein thecranking motor is energized simultaneously with the cranking motorsolenoid at low power through the parallel combination of the solenoidhold-in coil and a resistor whereby, in the event of pinion-crankinggear abutment, the motor provides torque to rotate the pinion gear intoindex with the cranking gear and a solenoid, energized only whencomplete pinion-cranking gear mesh is obtained, connects the crankingmotor across a source of direct current potential.

For a better understanding of the present invention, together withadditional objects, advantages and features thereof, reference is madeto the following description and accompanying drawing in which:

FIG. 1 sets forth, partially in schematic form, the improved internalcombustion engine cranking motor energizing circuit of this invention;

FIG. 2 is a schematic diagram of the electrical circuit portion of FIG.1;

FIG. 3 is a schematic diagram of another embodiment of the internalcombustion engine cranking motor energizing circuit of this inventionfor two cranking motors; and

FIG. 4 is a schematic diagram of another embodiment of the internalcombustion engine cranking motor energizing circuit of this inventionfor two cranking motors.

As point of reference or ground potential is the same point electricallythroughout the system, it has been illustrated in FIG. 1 by the acceptedschematic symbol and referenced by the numeral 5. 1

' the pinion gear 12 and the cranking gear 16 of an associated internalcombustion engine and a source of direct current potential, which may bea conventional storage battery 8. Electric cranking motors are usuallyof the series type, the series field and armature being shown in FIG. 1and referenced by the characters IOSF and A, respectively.

To operate the shift mechanism 15, an electrical solenoid 20 isprovided. Electrical solenoid 20 has a pull-in coil 21, a hold-in coil22, an armature member 23, an electrically conductive member 24 carriedby armature 23 and a pair of electrical contacts and 26. The armaturemember 23 is in operative engagement with shift mechanism 15. Armature23 is operated to a first position by a spring 17, in which position itis indicated in FIG. 1, and to a second position upon the energizationof pull-in coil 21 and hold-in coil 22 to effect, respectively, thedisengagement and engagement of pinion gear 12 with cranking gear 16.When armature member 23 has been actuated to the full extent of itstravel upon the energization of pull-in coil 21 and holdin coil 22,electrically conductive member 24, which may be of copper or aluminum orany other electrically conductive material, bridges electrical contacts25 and 26 to complete an electrical circuit thereacross. A resistor 27is connected in parallel across pull-in coil 21.

Upon the energization of pull-in .coil 21 and hold-in coil 22 ofcranking motor solenoid 20, armature member 23 is actuated by theresulting magnetic flux in a direction horizontally to the left, asviewing the FIG. 1. This motion rotates lever arm 13 in acounterclockwise direction around pivot point 14 and the end 18 of pivotarm 13 slides pinion gear 12 in a direction toward cranking gear 16 in amanner well known in the internal combustion engine cranking system art.

The current carrying elements of an electrical switching device of thetype having normally open current carrying elements operable to theelectrical circuit closed condition in response to an electrical signaland cranking motor 10 are connected in series across a source of directcurrent potential. The electrical switching device may be a conventionalelectric relay 30 having a movable contact 31, a stationary contact 32and an operating coil 33. The movable and stationary contact pair,31-32, of relay 30 and cranking motor 10 are connected in series acrossbattery 8 through a circuit which may be traced from the positivepolarity terminal of battery 8, through leads 34 and 35, movable andstationary contact pair 31-32 of relay 30, lead 36, series field 10SF,motor armature 10A and point of reference or ground potential 5 to thenegative polarity terminal of battery 8.

A relay 40 having two movable contacts 41 and 42 and two stationarycontacts 43 and 44 and an operating coil 45 is also provided.

An energizing circuit including one of the movable and stationarycontact pairs of relay 40 for each the pull-in coil 21 and parallelconnected resistor 27 and the cranking motor 10 in series and thehold-in coil 22 may be traced from the positive polarity terminal ofbattery 8, through lead 34, movable and stationary contact pair 41-43 ofrelay 40, lead 37, stub lead 38, to terminal 39 of cranking motorsolenoid 20 and thence through'a first parallel circuit includingpull-in coil 21 and parallel connected resistor 27, lead 29, and motor10 in series and through a second parallel circuit through hold-in coil22 and thence through point of reference or ground potential 5 to thenegative polarity terminal of battery 8.

An energizing circuit including the same one movable and stationarycontact pair of relay 40, the pair of electrical contacts 25 and 26 ofcranking motor solenoid 20 and the other movable and stationary contactpair of relay 40 for operating coil 33 of relay 30 may be traced fromthe positive polarity terminal of battery 8, through lead 34, movableand stationary contact pair 41-43 of relay 40, lead 37, contacts 25 and26 of cranking motor solenoid 20, lead 46, operating coil 33 of relay30, lead 47, movable and stationary contact pair 42-44 of relay 40, lead48 and point of reference or ground potential 5 to the negative polarityterminal of battery 8.

An energizing circuit for operating coil 45 of relay 40 may be tracedfrom the positive polarity terminal of battery 8, through leads 34 and49, the contacts of an electric crank switch 50, lead 55, operating coil45 and point of reference or ground potential 5 to the negative polarityterminal of battery 8. Electric crank switch 50 may be any one of theseveral momentary contact electric crank switches well known in the art.The armature member 51 of an electrically conductive material may beoperated into electrical engagement with stationary contacts 52 and 53to provide an electrically conductive bridge thereacross in a mannerwell known in the art.

Upon the operation of crank switch 50 to the electrical circuit closedcondition, the energizing circuit, previously described, for operatingcoil 45 of relay 40 is completed. Upon the energization of operatingcoil 45, movable and stationary contact pairs 41-43 and 42-44 areoperated to the electrical circuit closed condition. With movable andstationary contact pairs 41-43 and 42-44 of relay 40 in the electricalcircuit closed condition, the energizing circuit, previously described,for each pull-in coil 21 and parallel connected resistor 27 and crankingmotor 10 in series and for hold-in coil 22 is completed. Upon theenergization of pull-in coil 21 and hold-in coil 22, armature member .23of cranking motor solenoid 20 is actuated to operate shift mechanism 15to move pinion gear 12 axially in a direction operating coil 33, movableand stationary contact pair 31-32 of relay 30 are operated to theelectrical circuit closed condition. With movable and stationary contactpair 31-32 in the electrical circuit closed condition, an energizingcircuit is completed for cranking motor across battery 8 through acircuit which may be traced from the positive polarity terminal ofbattery 8, through lead 34, lead 35, movable and stationary contact pair31 and 32, lead 36, series winding 10SF and armature 10A of crankingmotor 10 and point of reference or ground potential 5 to the negativepolarity terminal of battery 8. Consequently, cranking motor 10 isoperated at full battery power to drive cranking gear 16 of theassociated internal combustion engine through shaft 11 and pinion gear12in a manner well known in the internal combustion engine crankingsystem art.

In the event of tooth to tooth abutment between pinion gear 12 andcranking gear 16 when movable and stationary contact pairs 41-43 and42-44 are initially operated to the electricalv circuit closedcondition, cranking motor 10 .is energized at reduced power through acircuit which may be traced from the positive polarity terminal ofbattery 8, through lead 34, movable and stationary contact pair 41-43 ofrelay 40, leads 37 and 38, terminal 39, the parallel combination ofpull-in coil 21 and resistor 27, lead 29, series field winding IOSF andarmature 10A of cranking motor 10 and point of reference or groundpotential 5 to the negative polarity terminal of battery 8. Resistor 27is selected to be of an ohmic value which, with respect to the ohmicvalue of pull-in coil 21, will permit sufficient current to flow throughcranking motor 10 to provide sufficient torque to rotate pinion gear 12to a position in which the teeth thereof are in index with the teeth ofcranking gear 16, at which time a mesh therebetween is obtained. At thistime, armature member 23 is actuated to the full extent of its travel tocomplete the energizing circuit, previously described, through whichcranking motor 10 is connected directly across battery 8 and is,therefore, energized by the full potential of battery 8.

FIG. 2 is a schematic diagram of the electrical portion of FIG. 1 whichmore clearly shows the detailed electrical circuit arrangement andconnections. In FIGS. 1 and 2, like elements have been assigned likecharacters of reference.

FIG. 3 is a schematic diagram of another embodiment of the internalcombustion engine cranking motor energizing circuit of this invention asapplied to two cranking motors referenced by the numerals 10a and 10b.In a two-cranking motor system, there are two cranking motor solenoidsand two associated shift mechanisms. In FIG. 3, the respective pull-incoils have been referenced by the numerals 21a and 21b, the respectivehold-in coils have been referenced by the numerals 22a and 22b, therespective armature members have been referenced by the numerals 23a and23b, the

respective electrical conductive members have beenreferenced by thenumerals 24a and 24b, the respective contacts have been referenced bythe numerals 25a and 25b and 26a and 26b and the respective resistorsconnected in parallel with the respective pull-in coils have beenreferenced by the numerals 27a and 27b. With this embodiment, relay 40has three movable and stationary contact pairs, the additional pairbeing referenced by the numerals 61 and 62, and relay 30 may have anadditional movable and stationary contact pair or, alternatively, aseparate relay having a single movable and stationary contact pair maybe employed. It is, however, believed to be preferable to have only onerelay with two movable and stationary contact pairs.

Uponthe operation of crank switch of the embodiment of FIG. 3 to theelectrical circuit closed condition, operating coil 45 of relay 40 isenergized to operate the associated movable and stationary contact pairs41-43, 42-44 and 61-62 to the electrical circuit closed condition. Atthis time, an energizing circuit is completed for the series combinationof pull-in coil 21a and parallel connected resistor 27a, cranking motor10a, cranking motor 10b, pull-in coil 21b and parallel connectedresistor 27b and for the series combination of hold-in coil 22a andhold-in coil 22b through movable and stationary contact pairs 41-43 and61-62. Upon the completion of this energizing circuit, respectivearmatures 23a and 23b are actuated in a direction which will cause theassociated respective shift mechanisms to move the respective piniongears of the respective cranking motors in the direction to engagecranking gear 16. If a mesh is obtained, respective electricallyconductive members 24a and 24b bridge respective contacts 250-260 and25b-26b. At this time, an energizing circuit is completed for operatingcoil 33 of relay 30 to operate movable and stationary contact pairs31-32 and 63-64 to the electrical circuit closed condition whichconnects cranking motors 10a and 10b in series across the source ofdirect current potential. In the event of tooth abutment upon theoperation of crank switch 50 to the electrical circuit closed condition,cranking motors 10a and 10b are operated at low power supplied theretothrough movable and stationary contact pair 41-43, the parallelcombination of pull-in coil 21a and resistor 27a, cranking motor 10a,cranking motor 10b, the parallel combination of pull-in coil 21b andresistor 27b and movable contact pair 61 and 62. Consequently, crankingmotors 10a and 10b provide torque to the respective pinion gears torevolve them to a position in which the teeth thereof are in registerwith the teeth of cranking gear 16. When a mesh between the respectivepinion gears and cranking gear 16 is obtained, the respective armaturemembers 23a and 23b are actuated to the full extent of their travel tocomplete the energizing circuit for operating coil 33 of relay 30through movable and stationary contact pair 43, stationary contacts 25aand 26a and electrically conductive member 240, operating coil 33,movable and stationary contact pair 42 and 44 of relay 40, stationarycontacts 25b and 26b and electrically conductive member 23b andstationary and movable contact pair 61 and 62 of relay 40. Upon thecompletion of this energizing circuit, movable and stationary contactpairs 31-32 and 63-64 of relay 30 are operated to the electrical circuitclosed condition to connect cranking motors 10a and 10b in series acrossthe source of direct current potential. Consequently, these motors areenergized by the full potential of the potential source.

FIG. 4 is a schematic diagram of another embodiment of the internalcombustion engine cranking motor energizing circuit of this inventionfor two series connected cranking motors 10a and 10b. This circuit issimilar to the circuit of FIG. 3 with the exception that movable contactpairs 61 and 62 of relay 40 and movable and stationary contact pair 63and 64 of relay 30 are omitted.

1n the embodiments of FIGS. 3 and 4, the cranking motors a and 10b areshown to be connected in series. lt is-to be specifically understoodthat cranking motors 10a and 10b may be connected in parallel with thesetwo embodiments without departing from the spirit of the invention.

While a preferred embodiment of the present invention has been shown anddescribed, it will be obvious to those skilled in the art that variousmodifications and substitutions may be made withoutdeparting from thespirit of the invention which is to be limited only within the scope ofthe appended claims.

' What is claimed is:

1. An internal combustion engine cranking motor energizing circuitcomprising in combination with a cranking system including an electriccranking motor having an extended shaft, a pinion gear slidably mountedupon and rotated by the extended motor shaft and a shift mechanismoperable to axially slide the pinion gear in one direction to engge andin an opposite direction to disengage the pinion gear and the crankinggear of the associated internal combustion engine and a source of directcurrent potential: an electrical solenoid having a pull-in coilconnected in series with saidcranking motor, a hold-in coil, an armaturemember in operative engagement with said shift mechanism which isoperated to a first position by a spring and to a second position uponthe energization of said pull-in and hold-in coils to effect,respectively, the disengagement and engagement of said pinion and enginecranking gears, an electrically conductive member carried by saidarmature and a pair of electrical contacts bridged by said electricallyconductive member when said armature is operated to said secondposition; a resistor connected in parallel across said pull-in coil; anelectrical switching device of the type having normally open currentcarrying elements operable to the electrical circuit closed condition inresponse to an electrical signal; means for connecting said currentcarrying elements of said electrical switching device and said crankingmotor in series across said source of direct current potential; a relayhaving two movable and stationary contact pairs and an operating coil;an energizing circuit including one of said. movable and stationarycontact pairs of said second relay for each said pull-in coil andparallel connected resistor and said cranking motor in series and saidhold-in winding; an electrical circuit including said same one movableand stationary contact pair of said second relay, said pair ofelectrical contacts of said solenoid and the other said movable andstationary contact pair of said second relay through which an electricalsignal may be supplied to said electrical switching device; an electriccrank switch; and an energizing circuit including said electric crankswitch for said operating coil of said second relay.

2. An internal combustion engine cranking motor energizing circuitcomprising in combination with a cranking system including an electriccranking motor having an extended shaft, a pinion gear slidably noidhaving a pull-in coil connected in series with said cranking motor, ahold-incoil, an armature member in operative engagement with said shiftmechanism whic is operated to a first position by a spring and to asecond position upon the energization of said pull-in and hold-in coilsto effect, respectively, the disengagement and engagement of said pinionand engine cranking gears, anelectrically conductive member carried bysaid armature and a pair of electrical contacts bridged by saidelectrically conductive member when said armature is operated to saidsecond position; a resistor connected in parallel across said pull-incoil; a first relay having a movable and stationary contact pair and anoperating coil; means for connecting said movable and stationary contactpair of said first relay and said cranking motor in series across saidsource of direct current potential; a second relay having two movableand stationary contact pairs and an operating coil; an energizingcircuit'including one of said movable and stationary contact pairs ofsaid second relay for each the series combination of said pull-in coiland parallel connected resistor and said cranking motor and for saidhold-in coil; an energizing circuit including said same one movable andstationary contact pair of said second relay, said pair of electricalcontacts of said solenoid and the other said movable and stationarycontact pair ing system including two electric cranking motors, eachhaving an extended shaft, a pinion gear slidably mounted upon androtated by the extended shaft of each motor and a shift mechanism foreach motor operable to axially slide the corresponding pinion gear inone direction to engage and in an opposite direction to disengage thepinion gear and the cranking gear of the associated'internal combustionengine and a source of direct current potential: an' electric solenoidcorresponding to each of said cranking motors, each of said solenoidshaving a pull-in coil, a hold-in coil, an armature member in operativeengagement with the said shift mechanism for the motor to which itcorresponds which is operated to a first position by a spring and to asecond position upon the energization of said pull-in and hold-in coilsto effect, respectively, the disengagement and engagement of thecorresponding said pinion gear and engine cranking gear, an electricallyconductive member carried by said armature and a pair of electricalcontacts bridged by said electrically conductive member when saidarmature is operated to said second position; a resistor connected inparallel across the said pull-in coil of each of said electricsolenoids;a first relay having a movable and stationary contact pair and anoperating coil; means for connecting said movable and stationary contactpair of said first relay and said two cranking motors across said sourceof direct current potential: at second relay having two movable andstationary contact pairs and an operating coil; an energizing circuitincluding one of said movable and stationary contact pairs of saidsecond relay for each the series combination of said pull-in coil andparallel connected resistor of one of said solenoids, said two crankingmotors and said pull-in coil and parallel connected resistor of saidsecond solenoid and the series combination of said hold-in coil of bothsaid solenoids; an energizing circuit including said same one of saidmovable and stationary contact pairs of said second relay, said pair ofelectrical contacts of both said solenoids and the other said movableand stationary contact pair of said second relay for said operating coilof said first relay; an electric crank switch; and an energizing circuitincluding said electric crank switch for said operating coil of saidsecond relay.

4. An internal combustion engine cranking motor energizing circuitcomprising in combination with a cranking system including two electriccranking motors, each having an extended shaft, a pinion gear slidablymounted upon and rotated by the extended shaft of each motor and a shiftmechanism for each motor operable to axially slide the correspondingpinion gear in one direction to engage and in an opposite direction todisengage the pinion gear and the cranking gear of the associatedinternal combustion engine and a source of direct current potential: anelectric solenoid corresponding to each of said cranking motors, each ofsaid solenoids having a pull-in coil connected in series with the saidcranking motor to which it corresponds, a hold-in coil, an armaturemember in operative engagement with the said shift mechanism for themotor to which it corresponds which is operated to a first position by aspring and to a second position upon the energization of said pull-inand hold-in coils to effect, respectively, the disengagement andengagement of the corresponding said pinion gear and engine crankinggear, an electrically conductive member carried by said armature and apair of electrical contacts bridged by said electrically conductivemember when said armature is operated to said second position; aresistor connected in parallel across the said pull-in coil of each ofsaid electric solenoids; a first relay having a movable and stationarycontact pair and an operating coil; means for connecting said movableand stationary contact pair of said first relay and said two crankingmotors in series across said source of direct current potential: asecond relay having two movable and stationary contact pairs and anoperating coil; an energizing circuit including one of said movable andstationary contact pairs of said second relay for each the seriescombination of said pull-in coil and parallel connected resistor of oneof said solenoids, said two cranking motors and said pull-in coil andparallel connected resistor of said second solenoid, in that order, andthe series combination of said hold-in coil of both said solenoids; anenergizing circuit including said same one of said movable andstationary contact pairs of said second relay, said pair of electricalcontacts of both said solenoids and the other said movable andstationary contact pair of said second relay for said operating coil ofsaid first relay; an electric crank switch; and an energizing circuitincluding said electric crank switch for said operating coil of saidsecond relay.

5. An internal combustion engine cranking motor energizing circuitcomprising in combination with a cranking system including two electriccranking motors, each having an extended shaft, a pinion gear slidablymounted upon and rotated by the extended shaft of each motor and a shiftmechanism for each motor operable to axially slide the correspondingpinion gear in one direction to engage and in an opposite direction todisengage the pinion gear and the cranking gear of the associatedinternal combustion engine and a source of direct current potential: anelectric solenoid corresponding to each of said cranking motors, each ofsaid solenoids having a pull-in coil connected in series with the saidcranking motor to which it corresponds, a hold-in coil, an armaturemember in operative engagement with the said shift mechanism for themotor to which it corresponds which is operated to a first position by aspring and to a second position upon the energization of said pull-inand hold-in coils to effect, respectively, the disengagement andengagement of the corresponding said pinion gear and engine crankinggear, an electrically conductive member carried by said armature and apair of electrical contacts bridged by said electrically conductivemember when said armature is operated to said second position; aresistor connected in parallel across the said pull-in coil of each ofsaid electric solenoids; a first relay having a movable and stationarycontact pair and an operating coil; means for connecting said movableand stationary contact pair of said first relay and said two crankingmotors across said source of direct current potential: a second relayhaving three movable and stationary contact pairs and an operating coil;an energizing'circuit including two of said movable and stationarycontact pairs of said second relay for each the series combination ofsaid pull-in coil and parallel connected resistor of one of saidsolenoids, said two cranking motors and said pull-in coil and parallelconnected resistor of said second solenoid and the series combination ofsaid hold-in coil of both said solenoids; an energizing circuitincluding said same two of said movable and stationary contact pairs ofsaid second relay, said pair of electrical contacts of both saidsolenoids and the other said movable and stationary contact pair of saidsecond relay for said operating coil of said first relay; an electriccrank switch; and an energizing circuit including said electric crankswitch for said operating coil of said second relay. 6. An internalcombustion engine cranking motor energizing circuit comprising incombination with a cranking system including two electric crankingmotors, each having an extended shaft, a pinion gear slidably mountedupon and rotated by the extended shaft of each motor and a shiftmechanism for each motor operable to axially slide the correspondingpinion gear in one direction to engage and in an opposite direction todisengage the pinion gear and the cranking gear of the associatedinternal combustion engine and a source of direct current potential: anelectric solenoid corresponding to each of said cranking motors, each ofsaid solenoids having a pull-in coil connected in series with the saidcranking motor to which it corresponds, a hold-in coil, an armaturemember in operative engagement with the said shift mechanism for themotor to which it corresponds which is operated to a first position by aspring and to a second position upon the energization of said pull-inand hold-in coils to effect, respectively, the disengagement andengagement of the corresponding said pinion gear and engine crankinggear, an electrically conductive member carried by said armature and apair of electrical contacts bridged by said electrically conductivemember when said armature is operated to said second position; aresistor connected in parallel across the said pull-in coil of each ofsaid electric solenoids; a first relay having two movable ill arycontact pairs of said first relay across said source of direct currentpotential: a second relay having three movable and stationary contactpairs and an operating coil; an energizing circuit including two of saidmovable and stationary contact pairs of said second relay for each theseries combination of said pull-in coil and parallel connected resistorof one of said solenoids, said two cranking motors and said pull-in coiland parallel connected resistor of said second solenoid and the seriescombination of said hold-in coil of both said solenoids; an energizingcircuit including said same two of I ably mounted upon and rotated bythe extended shaft of each motor and a shift mechanism for each motoroperable to axially slide the corresponding pinion gear in one directionto engage and in an opposite direction to disengage the pinion gear andthe cranking gear of the associated internal combustion engine and asource of direct current potential: an electric solenoid correspondingto each of said cranking motors, each of said solenoids having a pull-incoil connected in series with the said cranking motor to which itcorresponds, a hold-in coil, an armature member in operative engagementwith the said shift mechanism for the motor to which it correspondswhich is operated to a first position by a spring and to a secondposition upon the energization of said pull-in and hold-in coils toeffect, respectively, the disengagement and engagement of thecorresponding said pinion gear and engine cranking gear, an electricallyconductive member carried by said armature and a pair of electricalcontacts bridged by said electrically conductive member when saidarmature is operated to said second position; a resistor connected inparallel across the said pull-in coil of each of said electricsolenoids; a first relay having two movable and stationary contact pairsand an operating coil; means for connecting one of said movable andstationary contact pairs of said first relay, said two cranking motorsand the other one of said movable and stationary contact pairs of saidfirst relay in series across said source of direct current potential, inthat order; a second relay having three movable and stationary contactpairs and an operating coil; an energizing circuit including two of saidmovable and stationary contact pairs of said second relay for each theseries combination of said pull-in coil and parallel connected resistorof one of said solenoids, said two cranking motors and said pull-in coiland parallel connected resistor of said coil of said second relay.

=l l =i

1. An internal combustion engine cranking motor energizing circuitcomprising in combination with a cranking system including an electriccranking motor having an extended shaft, a pinion gear slidably mountedupon and rotated by the extended motor shaft and a shift mechanismoperable to axially slide the pinion gear in one direction to engge andin an opposite direction to disengage the pinion gear and the crankinggear of the associated internal combustion engine and a Source of directcurrent potential: an electrical solenoid having a pull-in coilconnected in series with said cranking motor, a hold-in coil, anarmature member in operative engagement with said shift mechanism whichis operated to a first position by a spring and to a second positionupon the energization of said pull-in and hold-in coils to effect,respectively, the disengagement and engagement of said pinion and enginecranking gears, an electrically conductive member carried by saidarmature and a pair of electrical contacts bridged by said electricallyconductive member when said armature is operated to said secondposition; a resistor connected in parallel across said pull-in coil; anelectrical switching device of the type having normally open currentcarrying elements operable to the electrical circuit closed condition inresponse to an electrical signal; means for connecting said currentcarrying elements of said electrical switching device and said crankingmotor in series across said source of direct current potential; a relayhaving two movable and stationary contact pairs and an operating coil;an energizing circuit including one of said movable and stationarycontact pairs of said second relay for each said pull-in coil andparallel connected resistor and said cranking motor in series and saidhold-in winding; an electrical circuit including said same one movableand stationary contact pair of said second relay, said pair ofelectrical contacts of said solenoid and the other said movable andstationary contact pair of said second relay through which an electricalsignal may be supplied to said electrical switching device; an electriccrank switch; and an energizing circuit including said electric crankswitch for said operating coil of said second relay.
 2. An internalcombustion engine cranking motor energizing circuit comprising incombination with a cranking system including an electric cranking motorhaving an extended shaft, a pinion gear slidably mounted upon androtated by the extended shaft and a shift mechanism operable to axiallyslide the pinion gear in one direction to engage and in an oppositedirection to disengage the pinion gear and the cranking gear of theassociated internal combustion engine and a source of direct currentpotential: an electrical solenoid having a pull-in coil connected inseries with said cranking motor, a hold-in coil, an armature member inoperative engagement with said shift mechanism which is operated to afirst position by a spring and to a second position upon theenergization of said pull-in and hold-in coils to effect, respectively,the disengagement and engagement of said pinion and engine crankinggears, an electrically conductive member carried by said armature and apair of electrical contacts bridged by said electrically conductivemember when said armature is operated to said second position; aresistor connected in parallel across said pull-in coil; a first relayhaving a movable and stationary contact pair and an operating coil;means for connecting said movable and stationary contact pair of saidfirst relay and said cranking motor in series across said source ofdirect current potential; a second relay having two movable andstationary contact pairs and an operating coil; an energizing circuitincluding one of said movable and stationary contact pairs of saidsecond relay for each the series combination of said pull-in coil andparallel connected resistor and said cranking motor and for said hold-incoil; an energizing circuit including said same one movable andstationary contact pair of said second relay, said pair of electricalcontacts of said solenoid and the other said movable and stationarycontact pair of said second relay for said operating coil of said firstrelay; an electric crank switch; and an energizing circuit includingsaid electric crank switch for said operating coil of said second relay.3. An internal combustion engine cranking motor energizing circuitcomprising in combustion with a crAnking system including two electriccranking motors, each having an extended shaft, a pinion gear slidablymounted upon and rotated by the extended shaft of each motor and a shiftmechanism for each motor operable to axially slide the correspondingpinion gear in one direction to engage and in an opposite direction todisengage the pinion gear and the cranking gear of the associatedinternal combustion engine and a source of direct current potential: anelectric solenoid corresponding to each of said cranking motors, each ofsaid solenoids having a pull-in coil, a hold-in coil, an armature memberin operative engagement with the said shift mechanism for the motor towhich it corresponds which is operated to a first position by a springand to a second position upon the energization of said pull-in andhold-in coils to effect, respectively, the disengagement and engagementof the corresponding said pinion gear and engine cranking gear, anelectrically conductive member carried by said armature and a pair ofelectrical contacts bridged by said electrically conductive member whensaid armature is operated to said second position; a resistor connectedin parallel across the said pull-in coil of each of said electricsolenoids; a first relay having a movable and stationary contact pairand an operating coil; means for connecting said movable and stationarycontact pair of said first relay and said two cranking motors acrosssaid source of direct current potential: a second relay having twomovable and stationary contact pairs and an operating coil; anenergizing circuit including one of said movable and stationary contactpairs of said second relay for each the series combination of saidpull-in coil and parallel connected resistor of one of said solenoids,said two cranking motors and said pull-in coil and parallel connectedresistor of said second solenoid and the series combination of saidhold-in coil of both said solenoids; an energizing circuit includingsaid same one of said movable and stationary contact pairs of saidsecond relay, said pair of electrical contacts of both said solenoidsand the other said movable and stationary contact pair of said secondrelay for said operating coil of said first relay; an electric crankswitch; and an energizing circuit including said electric crank switchfor said operating coil of said second relay.
 4. An internal combustionengine cranking motor energizing circuit comprising in combination witha cranking system including two electric cranking motors, each having anextended shaft, a pinion gear slidably mounted upon and rotated by theextended shaft of each motor and a shift mechanism for each motoroperable to axially slide the corresponding pinion gear in one directionto engage and in an opposite direction to disengage the pinion gear andthe cranking gear of the associated internal combustion engine and asource of direct current potential: an electric solenoid correspondingto each of said cranking motors, each of said solenoids having a pull-incoil connected in series with the said cranking motor to which itcorresponds, a hold-in coil, an armature member in operative engagementwith the said shift mechanism for the motor to which it correspondswhich is operated to a first position by a spring and to a secondposition upon the energization of said pull-in and hold-in coils toeffect, respectively, the disengagement and engagement of thecorresponding said pinion gear and engine cranking gear, an electricallyconductive member carried by said armature and a pair of electricalcontacts bridged by said electrically conductive member when saidarmature is operated to said second position; a resistor connected inparallel across the said pull-in coil of each of said electricsolenoids; a first relay having a movable and stationary contact pairand an operating coil; means for connecting said movable and stationarycontact pair of said first relay and said two cranking motors in seriesacross said source of direct current potential: a second relay havingtwo movable and stationary contact pairs and an operating coil; anenergizing circuit including one of said movable and stationary contactpairs of said second relay for each the series combination of saidpull-in coil and parallel connected resistor of one of said solenoids,said two cranking motors and said pull-in coil and parallel connectedresistor of said second solenoid, in that order, and the seriescombination of said hold-in coil of both said solenoids; an energizingcircuit including said same one of said movable and stationary contactpairs of said second relay, said pair of electrical contacts of bothsaid solenoids and the other said movable and stationary contact pair ofsaid second relay for said operating coil of said first relay; anelectric crank switch; and an energizing circuit including said electriccrank switch for said operating coil of said second relay.
 5. Aninternal combustion engine cranking motor energizing circuit comprisingin combination with a cranking system including two electric crankingmotors, each having an extended shaft, a pinion gear slidably mountedupon and rotated by the extended shaft of each motor and a shiftmechanism for each motor operable to axially slide the correspondingpinion gear in one direction to engage and in an opposite direction todisengage the pinion gear and the cranking gear of the associatedinternal combustion engine and a source of direct current potential: anelectric solenoid corresponding to each of said cranking motors, each ofsaid solenoids having a pull-in coil connected in series with the saidcranking motor to which it corresponds, a hold-in coil, an armaturemember in operative engagement with the said shift mechanism for themotor to which it corresponds which is operated to a first position by aspring and to a second position upon the energization of said pull-inand hold-in coils to effect, respectively, the disengagement andengagement of the corresponding said pinion gear and engine crankinggear, an electrically conductive member carried by said armature and apair of electrical contacts bridged by said electrically conductivemember when said armature is operated to said second position; aresistor connected in parallel across the said pull-in coil of each ofsaid electric solenoids; a first relay having a movable and stationarycontact pair and an operating coil; means for connecting said movableand stationary contact pair of said first relay and said two crankingmotors across said source of direct current potential: a second relayhaving three movable and stationary contact pairs and an operating coil;an energizing circuit including two of said movable and stationarycontact pairs of said second relay for each the series combination ofsaid pull-in coil and parallel connected resistor of one of saidsolenoids, said two cranking motors and said pull-in coil and parallelconnected resistor of said second solenoid and the series combination ofsaid hold-in coil of both said solenoids; an energizing circuitincluding said same two of said movable and stationary contact pairs ofsaid second relay, said pair of electrical contacts of both saidsolenoids and the other said movable and stationary contact pair of saidsecond relay for said operating coil of said first relay; an electriccrank switch; and an energizing circuit including said electric crankswitch for said operating coil of said second relay.
 6. An internalcombustion engine cranking motor energizing circuit comprising incombination with a cranking system including two electric crankingmotors, each having an extended shaft, a pinion gear slidably mountedupon and rotated by the extended shaft of each motor and a shiftmechanism for each motor operable to axially slide the correspondingpinion gear in one direction to engage and in an opposite direction todisengage the pinion gear and the cranking gear of the associatedinternal combustion engine and a source of direct current potential: anelectric solEnoid corresponding to each of said cranking motors, each ofsaid solenoids having a pull-in coil connected in series with the saidcranking motor to which it corresponds, a hold-in coil, an armaturemember in operative engagement with the said shift mechanism for themotor to which it corresponds which is operated to a first position by aspring and to a second position upon the energization of said pull-inand hold-in coils to effect, respectively, the disengagement andengagement of the corresponding said pinion gear and engine crankinggear, an electrically conductive member carried by said armature and apair of electrical contacts bridged by said electrically conductivemember when said armature is operated to said second position; aresistor connected in parallel across the said pull-in coil of each ofsaid electric solenoids; a first relay having two movable and stationarycontact pairs and an operating coil; means for connecting one of saidmovable and stationary contact pairs of said first relay, said twocranking motors and the other one of said movable and stationary contactpairs of said first relay across said source of direct currentpotential: a second relay having three movable and stationary contactpairs and an operating coil; an energizing circuit including two of saidmovable and stationary contact pairs of said second relay for each theseries combination of said pull-in coil and parallel connected resistorof one of said solenoids, said two cranking motors and said pull-in coiland parallel connected resistor of said second solenoid and the seriescombination of said hold-in coil of both said solenoids; an energizingcircuit including said same two of said movable and stationary contactpairs of said second relay, said pair of electrical contacts of bothsaid solenoids and the other said movable and stationary contact pair ofsaid second relay for said operating coil of said first relay; anelectric crank switch; and an energizing circuit including said electriccrank switch for said operating coil of said second relay.
 7. Aninternal combustion engine cranking motor energizing circuit comprisingin combination with a cranking system including two electric crankingmotors, each having an extended shaft, a pinion gear slidably mountedupon and rotated by the extended shaft of each motor and a shiftmechanism for each motor operable to axially slide the correspondingpinion gear in one direction to engage and in an opposite direction todisengage the pinion gear and the cranking gear of the associatedinternal combustion engine and a source of direct current potential: anelectric solenoid corresponding to each of said cranking motors, each ofsaid solenoids having a pull-in coil connected in series with the saidcranking motor to which it corresponds, a hold-in coil, an armaturemember in operative engagement with the said shift mechanism for themotor to which it corresponds which is operated to a first position by aspring and to a second position upon the energization of said pull-inand hold-in coils to effect, respectively, the disengagement andengagement of the corresponding said pinion gear and engine crankinggear, an electrically conductive member carried by said armature and apair of electrical contacts bridged by said electrically conductivemember when said armature is operated to said second position; aresistor connected in parallel across the said pull-in coil of each ofsaid electric solenoids; a first relay having two movable and stationarycontact pairs and an operating coil; means for connecting one of saidmovable and stationary contact pairs of said first relay, said twocranking motors and the other one of said movable and stationary contactpairs of said first relay in series across said source of direct currentpotential, in that order; a second relay having three movable andstationary contact pairs and an operating coil; an energizing circuitincluding two of said movable and stationary contact pairs of saidsecond relay for each the series combination of said pull-in coil andparallel connected resistor of one of said solenoids, said two crankingmotors and said pull-in coil and parallel connected resistor of saidsecond solenoid, in that order, and the series combination of saidhold-in coil of both said solenoids; an energizing circuit includingsaid same two of said movable and stationary contact pairs of saidsecond relay, said pair of electrical contacts of both of said solenoidsand the other said movable and stationary contact pair of said secondrelay for said operating coil of said first relay; an electric crankswitch; and an energizing circuit including said electric crank switchfor said operating coil of said second relay.